Replace peep with pip hash checking when building docker.

Dockerfile

@@ -7,7 +7,7 @@ RUN apt-get update && \
     apt-get install -y --no-install-recommends \
     build-essential libxml2-dev libxslt1-dev libffi-dev python-dev \
     libmysqlclient-dev python-pip node-less locales && \
-    pip install --upgrade pip==7.0.3 && \
+    pip install --upgrade pip==8.0.3 && \
     rm -rf /var/lib/apt/lists/*
 RUN dpkg-reconfigure locales && locale-gen C.UTF-8 && \
     /usr/sbin/update-locale LANG=C.UTF-8
@@ -17,5 +17,4 @@ ENV LANG en_US.UTF-8
 ENV LANGUAGE en_US.UTF-8
 
 COPY requirements /code/requirements/
-COPY bin/peep.py /code/bin/peep.py
-RUN python bin/peep.py install --no-cache-dir -r requirements/dev.txt
+RUN pip install --require-hashes --no-deps -r requirements/dev.txt